The invention relates to an airless type dispenser and more particularly to an airless type dispenser in which a problem like a chemical reaction between a cosmetic substance and the piston material can be prevented, and accordingly wrong operation can be avoided.
There are two types of conventional dispensers wherein a predetermined quantity of cosmetics substance or the like is ejected by air pressure. One of which is a dip tube type wherein the substance is sucked and ejected by the dip tube and the corresponding quantity of air comes in, and the other of which is the airless type wherein a piston is ascended and the substance is pushed up according as the air comes in the receptacle evacuates. FIG. 1 shows the airless type dispenser of the prior art. As shown in FIG. 1, the upper end of the receptacle is covered with a dispenser cap 12. This dispenser cap 12 includes a pump 14, a button 15, and nozzle 16. And a piston 18 is provided in the receptacle 11 airtightly. Conventionally, the piston 18 was generally made with the polyethylene resin. The reason is that, if the piston is made of polyethylene resin, it has excellent flexibility, elasticity and lubrication, and accordingly, airtightness between the piston and the inner wall of the receptacle can be secured. In addition, the piston can be readily slidable along the inner wall.
Also, the prior art polyethylene piston 18 can cause some troubles if it reacts with a pigment dispersant which may be included as a cosmetic substance. In that case, many kinds of critical defects may be resulted. One of these defects is the piston 18 may not slide along the inner wall of the receptacle 11 because the pigment dispersant which may be for foundation or makeup base is absorbed into the polyethylene piston 18 and causes swelling of the piston 18, or the airtightness may be destroyed owing to irregular swelling. As stated above, because the polyethylene piston has high expansibility it can easily absorb cosmetic substances that contain pigment dispersant, thus, causing swelling of the piston 18 which causes defects to dispenser products.
The present invention solves the above described problems by providing an airless type dispenser that can prevent chemical reactions between cosmetic substances and the piston material.
According to an aspect of the invention, an airless dispenser is provided. The airless dispenser comprises a receptacle 11, a piston 18 inserted in the receptacle 11, a dispenser cap 12 which is coupled to the opening of the upper end of the receptacle 11 and includes a pump, a button and a nozzle, wherein on the upper surface of piston 18 is laminated with a material which has a lower expansibility than the piston.